 s1_generate_a_series_of_files(){
	for i in {1..100};
	do
	echo $i>/tmp/new_file$i;
	done
}

function s2_list_4_files_in_long_format_about_account_and_group(){
	ls -l /etc/{passwd,shadow,group,gshadow} | sort
}

function s3_find_items_related_to_given_username(){
	grep -h $1 /etc/{passwd,shadow} | sort
}

function s4_find_items_related_to_given_group_name(){
	grep -h $1 /etc{group,gshadow} | sort
}

function s5_create_groups_for_given_group_names(){
	groupadd rnd
	groupadd itoperation
}

function s6_create_users_and_set_their_group_as_required(){
	useradd adam
	useradd bob
	useradd calvin
	useradd david
	useradd edward
	usermod -a -G rnd adam
	usermod -a -G rnd bob
	usermod -a -G rnd edward
	usermod -a -G itoperation calvin
	usermod -a -G itoperation david
}

function s7_change_users_shell(){
	usermod -s /usr/bin/sh adam
	usermod -s /usr/bin/sh edward
}

function s8_set_password_change_policy(){
	passwd -n 10 -x 60 -w 10 adam
	passwd -n 10 -x 60 -w 10 bob
	passwd -n 10 -x 60 -w 10 david
	passwd -n 10 -x 60 -w 10 calvin
	passwd -n 10 -x 60 -w 10 edward
}

function s9_set_password_for_five_users(){
	usernames=(adam bob calvin david edward) 
	passwords=("$1" "$2" "$3" "$4" "$5")
	for i in $(seq 0 4);do
	echo "${usernames[$i]}:${passwords[$i]}" | sudo chpasswd
	done
}

function s10_lock_bobs_password(){
	usermod -L bob
}

function s11_include_adam_into_wheel_group(){
	sudo usermod -a -G wheel adam
}

function s12_change_files_permission(){
	for i in {1..100};
	do
		filename="/tmp/new_file${i}" > $filename
		if (($i % 3 == 0));
		then
			sudo chmod 640 $filename
		fi
	done
}
